Apparatus, system and method for underwater signaling of audio messages to a diver

ABSTRACT

Embodiments of the invention provide a system, apparatus and methods for underwater voice communication between a diver and an underwater electronic device. In many embodiments, the system includes a dive computer which generates audio signals corresponding to spoken messages and a mouthpiece apparatus having an acoustic transducer that conducts sound via conduction through the diver&#39;s teeth and skull to the cochlea so as to allow the diver to hear the messages and other sounds and a microphone for sensing the diver&#39;s voice. The mouthpiece is adapted to be easily attached to portions of a SCUBA or other underwater breathing apparatus. It may also be attached or integral to a snorkel or similar apparatus.

RELATED APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 61/444,571, filed Feb. 18, 2011, entitled“APPARATUS, SYSTEM AND METHOD FOR UNDERWATER SIGNALING OF AUDIO MESSAGESTO A DIVER”, which is fully incorporated by reference herein for allpurposes.

This application is related to U.S. patent application Ser. No.13/352,249, filed Jan. 17, 2012, entitled “APPARATUS, SYSTEM AND METHODFOR UNDERWATER VOICE COMMUNICATION BY A DIVER”, which claims priority toU.S. Provisional Patent Application No. 61/433,168, filed Jan. 14, 2011,entitled “APPARATUS, SYSTEM AND METHOD FOR UNDERWATER VOICECOMMUNICATION BY A DIVER”; U.S. patent application Ser. No. 13/237,912,filed Sep. 20, 2011, entitled “DEVICE, SYSTEM AND METHOD FOR MONITORINGAND COMMUNICATING BIOMETRIC DATA OF A DIVER”, which claims priority toU.S. Provisional Patent Application No. 61/384,612, filed Sep. 20, 2010,entitled “DEVICE, SYSTEM AND METHOD FOR MONITORING AND COMMUNICATINGBIOMETRIC DATA OF A DIVER”; and U.S. patent application Ser. No.13/231,881, filed Sep. 13, 2011, entitled “SELF-PROPELLED BUOY FORMONITORING UNDERWATER OBJECTS”, which claims priority to U.S.Provisional Patent Application No. 61/382,438, filed Sep. 13, 2010,entitled “SELF-PROPELLED BUOY FOR MONITORING UNDERWATER OBJECTS”; all ofthe aforementioned applications being incorporated by reference hereinfor all purposes.

FIELD OF THE INVENTION

Embodiments described herein relate to a system for underwater voicecommunication. More specifically, embodiments described herein relate toan apparatus, system and method for underwater communication by a diver,such as SCUBA or skin diver.

BACKGROUND

Since the early days of SCUBA (Self Contained Underwater BreathingApparatus) diving with Jacque Cousteau, communication between SCUBAdivers has been an issue. This is due to the fact that: i) the use ofthe SCUBA breathing apparatus (including a mouthpiece worn by the diverprecludes direct voice communication, and ii) because of risks of theunderwater environment, divers have a critical need to communicate avariety of safety related messages to their fellow divers, e.g.,communicating the amount of air they have remaining (a maxim of divingis to never dive alone, but instead always go with at least one otherdiver known as a “dive buddy”). As a result, a series of hand signs havebeen developed but these only cover a very limited number of messagesand cannot quickly get the other diver's attention in criticalsituations. Various underwater graphical display devices have also beendeveloped, but these have the same limitation. These devices which areworn on the diver's wrist or arm require the diver to divert his or herattention from what they are doing to look at the display. Typically,divers dive with their head up to see where they are going and theirarms at their sides to reduce water resistance. So, the diver's naturaldiving position is not conducive to monitoring a visual alert on theirwrist or elsewhere (e.g., arm or waist). This is even true for visualalerts on the diver's face mask since the diver's attention is morefocused on what is in front of them and not their face mask.

Acoustic alarm systems have been developed but they are not voice basedand can only communicate a limited number of messages which require thediver to understand an alarm code. Also, none of these devices providefor communication between divers and a surface craft such as the diveboat (the boat which supports the divers). Further none of these devicesprovides for communication between divers who are not in very closeproximity. What is needed is an approach allowing for voicecommunication between divers while they are underwater as well as forvoice communication between divers and a surface craft.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the invention provide a system, apparatus and methods forunderwater voice communication by a diver to other divers and surfaceships as well as between a diver and an underwater electronic devicewhich generates voice messages for the diver. In many embodiments, thesystem includes a dive computer or like device having the ability togenerate audio messages and a mouthpiece having an acoustic transducerthat conducts sound via conduction through the diver's teeth and skullto the cochlea so as to allow the diver to hear the audio messages andother sounds and a microphone for sensing the diver's voice. Themouthpiece is adapted to be easily attached to portions of a SCUBA orother underwater breathing apparatus. It may also be attached to orintegrated with a snorkel or similar apparatus. One or both of themouthpiece and the dive computer may include circuitry for amplifyinghigher frequency components of the audio messages or other sounds toaccount for reduced level of conduction of such frequencies by bone.

Embodiments of the invention allow the diver to speak and have two wayvoice communication with other divers and surface ships without havingto remove their mouthpiece and without having any other specializedequipment. Embodiments of the invention also allow the diver to hearaudio messages such as acoustic alarms, voice messages and prompts froma portable dive computer or other underwater electronic device. In use,such embodiments allow the diver to perform various tasks whilereceiving a variety of information including voice prompts and commandswithout having to look at a display or gauge. This enables the divers tostay focused on their task and/or their underwater environment thusimproving safety and their diving experience. Still other embodiments ofthe invention allow the diver to hear music, radio or other audio inputwhile they are underwater. Still other embodiments can provide the diverwith an acoustic input of sounds from the body of water in which he orshe is diving allowing the diver to hear the sounds of underwater marinelife as well as the sounds of surface craft.

In one embodiment, the invention provides a mouthpiece apparatus forunderwater voice communication by a diver comprising a mouthpiece havingan exterior coupling element for coupling to an air hose or otherconduit of a SCUBA (or other underwater breathing apparatus) and aninterior portion coupled to the coupling element and worn in the diver'smouth. The coupling element may be coupled directly to the air hose orto a fitting on the air hose. The coupling element and interior portioncan include a lumen for the passage of respired air by the diver. Theinterior portion has a curved shaped corresponding to a shape of thediver's mouth and has attached right and left bite structures. The bitestructures include upper and lower surfaces for engaging a bite surfaceof the user's upper and lower teeth. One or both of the bite structuresmay include a retaining flange which can be perpendicular to a bitesurface of the bite structure for retaining the mouthpiece in thediver's mouth.

An acoustic transducer is positioned on the top surface of at least oneof the left or right bite structures. The acoustic transducer isconfigured to transduce an electrical signal input (e.g., from anothercommunication device) into an acoustic output and to acoustically coupleto the diver's upper teeth in order to conduct the acoustic output fromthe diver's upper teeth through the skull to generate audible sound inat least one of the diver's ears when the diver is wearing themouthpiece. Typically, the acoustic transducer is positioned to engagethe upper (e.g., maxillary) back teeth of the diver's mouth, but may bepositioned to engage any tooth or group of teeth in the diver's mouth.Also, transducer properties can be tuned or otherwise adjusted. Amicrophone is positioned in or on the mouthpiece for detecting thediver's voice and generating an electrical output signal when the diveris wearing the mouthpiece. The microphone may be recessed or otherwisepositioned to reduce breathing sounds. This microphone output can besent to an underwater communication device for underwater transmissionto another diver(s) or to a surface ship. In many embodiments, thecommunication device may correspond to an ultrasonic or other acousticaltransmission device which transduces the electrical output signal intoan acoustic signal, which is transmitted by the acoustical transmissiondevice. Also, in various embodiments, one or both of the communicationdevice or microphone may include a filter (e.g., high pass, low pass,etc.) for filtering out breath and related sounds of the diver from hisor her spoken words.

In an exemplary embodiment of using the invention, the diver attaches anembodiment of the mouthpiece to a fitting on a regulator or othercomponent of his or her SCUBA gear. For embodiments having electricalcouplings on the mouthpiece, the diver may then connect them to theunderwater communication device. He or she may perform a few quick teststo assure that the communication system is working. Such tests caninclude putting in the mouthpiece and saying some test phrases (e.g.,“testing 1, 2, 3,” etc.) while looking at a display on or coupled to thecommunication device to assure that a signal from the microphone isgetting to the communication device. The test for the acoustictransducer can comprise putting in the mouthpiece and pressing a testsignal button on the communication device which then sends a test signalto the acoustical transducer, which converts the electrical signal to anaudio signal conducted through his teeth and skull, and which the diverthen listens for. For either test, the diver can move the mouthpiecearound in his or her mouth to find a position of the mouthpiece in theirmouth which yields the best output signal from the microphone. The divermay perform a similar procedure for embodiments of the mouthpiece usedin a snorkel. Having found that position, the diver may select aparticular acoustic frequency or range of frequencies (e.g., akin to achannel) to use for input (hearing) and output (verbal speech). Thediver may choose to use the system underwater for voice communicationwith other divers as well as surface ship. Depending upon thefrequencies available, the diver may then select/assign a distinctacoustic frequency or frequency range for a particular diver as well asfor a surface craft. In many embodiments, the system will allow forseparate frequency and/or frequency range to minimize cross talk fromdiver to diver as well as diver to surface ship communication. These andother aspects, embodiments and features are described in detail in thebody of specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of an underwater voicecommunication system for a diver.

FIG. 1 a shows an embodiment of a voice communication mouthpieceapparatus worn in the mouth and its use in the conduction of sound tothe inner ear through the skull.

FIG. 2 is a lateral view illustrating embodiments of the mouthpiececoupled to an underwater breathing apparatus such as a SCUBA.

FIG. 3 is a perspective view showing various features of an embodimentof the mouthpiece.

FIG. 4 is a lateral view showing an embodiment of the mouthpiece havingan electrical connection means such as a wire for coupling to PWEdevices such as a dive computer.

FIG. 5 a is a side cut-away view showing an embodiment of the mouthpiecehaving a cavity and a microphone positioned in the cavity.

FIG. 5 b is a block diagram illustrating the configuration and operationof an embodiment of the microphone.

FIG. 6 a is a side cut-away view showing an embodiment of the acoustictransducer comprising an electromagnetic driver, acoustical plate andconnecting lever.

FIG. 6 b is a top down view showing an embodiment of the acoustictransducer positioned in/on the mouthpiece.

FIG. 6 c is a block diagram showing the configuration and operation ofan embodiment of the acoustical transducer.

FIG. 6 d is a block diagram showing the configuration and operation ofan embodiment of a communication system for generating voice prompts andother messages that are delivered to the diver by embodiments of theacoustical transducer.

FIG. 7 a is a top down view illustrating an embodiment of the acousticplate having a curved shape corresponding to curvature of the diver'sdental arches.

FIG. 7 b is a side view illustrating an embodiment of the acoustic platehaving conducting ridges.

FIG. 8 illustrates an embodiment of the mouthpiece having a wirelesscommunication device such as an RF communication chip for communicatingwith a diver computer or other PWE device.

FIG. 9 a is a cut away perspective view illustrating an embodiment of amultilayer mouthpiece having a rigid core and softer outer layer.

FIG. 9 b is a cut away top down view illustrating an embodiment of amultilayer mouthpiece having a rigid core and softer outer layer.

FIG. 10 is a schematic view illustrating the configuration and operationof an embodiment of the communication device for use with embodiments ofthe voice communication mouthpiece apparatus.

FIG. 11 is a schematic view illustrating the configuration and operationof an embodiment of a PWE device (such as a dive computer) including acommunication device for use with embodiments of the voice communicationmouthpiece apparatus.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1-11, an embodiment of a communication system 5(herein system 5) for voice communication from a first diver 200 to oneor more other divers 210 or surface ships 220 comprises a voicecommunication mouthpiece apparatus 10 (herein mouthpiece 10) and anunderwater communication device 100. In various embodiments,communication system also provides for communication of computergenerated voice messages to the diver from a portable underwater device.Mouthpiece 10 is worn in the diver's mouth and is configured to attachto a regulator 82 or other fitting 83 of a SCUBA or other underwaterdiving apparatus 80. System 5, including mouthpiece 10, is configured toallow voice or other communication between a first underwatercommunication device 100 carried by diver 200 and a second underwatercommunication device 110 carried by other diver(s) 210 as well asbetween communication device 100 and a communication device 130 used bya surface ship 220. In one embodiment, communication device 130 can beincorporated into a buoy or array towed by ship 220. With regard tocommunication device 100 (and 110), it can be positioned on a variety oflocations on the diver and/or on Scuba 80. In one embodiment, it may bepositioned on the diver's head and can be attached using a band or strapor it may be coupled to the hood of the diver's wetsuit. In manyembodiments, communication device 100 may be incorporated into aportable watertight electronic device 160 carried or worn by the diveras is described herein.

In addition to communication with another diver 210 having a separateSCUBA 80, in various embodiments, system 5 and mouthpiece 10 can also beadapted for communication with another mouthpiece 10′ connected to abuddy breathing line 16 connected to same SCUBA 80 as used by diver 200as is shown in the embodiment of FIG. 1. In such embodiments,mouthpieces 10 and 10′ can be configured to both be operativelyconnected to the same communication device 100 or they may be configuredto be directly connected to each other without the use of communicationdevice 100. In use, such embodiments allow quick and ready communicationbetween the diver 200 and the buddy breather without the need for anycommunication device or any set up procedure.

The mouthpiece 10 includes a coupling element 11, an interior portion 20coupled to the coupling element 11, a microphone 40 and an acoustictransducer 50. Coupling element 11, couples the mouthpiece 10 to SCUBA80. In various embodiments, coupling element 11 may be configured tocouple directly to an air hose 81 of SCUBA 80 or a regulator 82 or otherfitting 83 of SCUBA 80. The coupling element 11 and interior portion 20include a lumen 13 for the passage of respired air by the diver.

One or both of the microphone 40 and the acoustic transducer 50 may bepowered by a battery 90 which is incorporated into the mouthpiece 10 orcoupled to the mouthpiece 10, for example, by an electrical wire 17 orother electrical connection means 17. Battery 90 may comprise variouslithium buttons batteries or other miniature batteries known in the artand may be configured for underwater use (e.g., by having watertightseals and/or be manufactured according to various Mil-Spec standards,including those for diving gear). Battery 90 may also be shaped to havea form factor which readily fits into mouthpiece 10. For example, in oneembodiment, battery 90 may have a curved shape which corresponds to thecurvature of the diver's dental arches DA. Battery 90 may also be usedto power a processor 70 that may also be contained in the mouthpiece 10and described in more detail herein.

Wire(s) 17 may also be configured to couple both the microphone 40 andthe acoustic transducer 50 (as well as electrical components ofmouthpiece 10) to various electrical devices that are part of SCUBA 80or are otherwise worn or carried by the diver, such as communicationdevice 100 and/or dive computer 160. Wire(s) 17 may be insulatedsufficiently to withstand depths of several hundred feet or more. Aportion of the wires 17 may be embedded in the mouthpiece 10 and/orconnected to the mouthpiece 10 by an electrical connector configured forunderwater conditions. Wire 17 can include at least a first and secondwire for connection to the microphone 40 and the acoustic transducer 50.In some embodiments, a section of wire 17 may pass through lumen 13 ofcoupling element 11 so as to connect to one or more electrical devicesthat are part of SCUBA 80 or are otherwise worn or carried by the diver.In such embodiments, wire 17 is sufficiently thin or otherwiseconfigured so as to not interfere or impede the passage of respired airthrough lumen 13.

In alternative or additional embodiments, one or both of the microphone40 and the transducer 50 may be operatively coupled to communicationdevice 100 and/or dive computer 160 via use of a wireless communicationdevice 95, such as an RF communication chip 95 which may be embedded inthe mouthpiece 10. RF communication chip 95 may correspond to an activeor passive RF transceiver and may be embedded in the mouthpiece 10. Thefrequency and power levels for use with such an RF communication chip 95can be adapted for underwater use to allow communication of signals 97between an RF communication chip 95 in the mouthpiece 10 and acorresponding chip 96 in communication device 100 and/or dive computer160 carried by the diver. In use, such embodiments, allow the diver toreadily couple the mouthpiece 10 to communication device 100 and/or divecomputer 160 without having to make any electrical connections. It alsoallows the diver to verify that the mouthpiece 10 is operating properlybefore getting into the water through the use of one or more diagnosticsoftware modules 190 resident within dive computer 160 which can beconfigured to interrogate mouthpiece 10 for proper operation. In oneembodiment, this may consist of the diver being prompted to speakseveral test phrases with the mouthpiece in place. Further in variousembodiments, communication chip 95 and/or memory chip or other memoryresources 75 coupled to communication chip 95 may contain various diverspecific information (e.g., name, weight, health data, dive historyetc.) which can be signaled to dive computer 160 allowing the divecomputer to uniquely identify the mouthpiece 10 as belonging to aparticular diver and then upload that data into the dive computer. Theprocess may also be facilitated by use of a processor 70, (e.g., amicroprocessor 70), that controls the handshake and other communicationbetween communication chip 95 and chip 96. Processor 70 may also containor be coupled to memory resources 75. In particular embodiments, such aconfiguration can be implemented through use of an ASIC (applicationspecific integrated circuit) containing processor 70, memory resources75 and even battery 90.

The interior portion 20 of the mouthpiece 10 has a curved shape 21corresponding to a shape of the diver's dental arches DA and hasattached right 31 and left 32, bite structures 30. The curved shape 21may be fabricated by taking a dental impression or image of the diver'smouth and then using that impression or image to construct a mold formaking the mouthpiece and/or using stereolithography techniques known inthe art. The bite structures 30 include upper 33 and lower 34 surfaces35 (also called bite surfaces 35) for engaging a bite surface BS of thediver's upper teeth, UT (also called maxillary) and lower teeth, LT.Bite structures 30 may be positioned and arranged to contact at leastthe back teeth of the diver, but may contact the front teeth as well (orother teeth T or groups of teeth). The bite structures 30 may also beconfigured to be acoustically isolated from each other by fabricatingall or a portion of the bite structures from various acousticallyinsulating materials known in the art.

In various embodiments, one or both of the bite structures 30 mayinclude a retaining flange 36 for retaining the mouthpiece in thediver's mouth M by contacting an inside surface of the diver's teeth T.Typically, flange 36 will be oriented perpendicular to bite surfaces 35,but other orientations are also contemplated (e.g., an acute angle).Also, flange 36 may have a curved shape or profile 37 which correspondsto the curvature of the diver's dental arches DA.

In various embodiments, mouthpiece 10 may be fabricated from elastomericpolymers such as silicone, polyurethane, copolymers thereof and otherelastomers known in the art. The mouthpiece 10 may have a unitaryconstruction and or may be fabricated from separate components which arejoined. It may be fabricated using various methods known in the polymerprocessing arts, including molding and stereolithography methods. Also,molding may be done with the microphone 40 and/or acoustic transducer 50in place, or they may be added to cavities created in the mouthpiece 10for their positioning. The polymeric materials for the mouthpiece 10 maybe selected for several different mechanical and acoustical properties.For example the material can be selected to achieve a desired durometerfor the mouthpiece 10. The durometer of the material may be selected tomaintain the shape of the mouthpiece 10, but at the same time, reducethe bite force required for the diver to hold the mouthpiece 10 inplace. Suitable lower durometer embodiments include the range of about20 to 50, more preferably, about 30 to 40. In use, such lower durometerembodiments allow the diver to keep the mouthpiece 10 in their mouth forextended periods (e.g., hours) without excessive discomfort or fatigueof their jaw muscles, particularly while speaking. The properties of thepolymers used for the mouthpiece 10 can also be selected to obtain adesired amount of acoustical insulation so as to minimize thetransmission of sound from acoustic transducer 50 to microphone 40 so asto reduce or prevent feedback between the two.

In some embodiments, a mouthpiece 10 having a lower durometer can beachieved by use of a two-ply and/or other multilayer configurations 10 lof the mouthpiece 10 where at least a portion of the mouthpiece 10comprises a lower durometer tooth contacting surface layer 18 (alsoreferred to as a liner) which fits over a higher durometer (e.g., morerigid), underlying core structure 19. The latter provides sufficientrigidity for holding the shape of the mouthpiece 10 in the diver'smouth, while the former provides a soft comfortable tooth contactingsurface. Liner 18 may also be configured to provide acousticalinsulation/dampening properties so as to reduce feedback betweenmicrophone 40 and acoustic transducer 50 by reducing the transmission ofsound from transducer 50 and microphone 40. In use, such two ply orother multilayer embodiments of the mouthpiece 10 provide a morecomfortable mouthpiece and one that minimizes or reduces feedback fromthe transducer 50 and microphone 40, while maintaining the shape of themouthpiece. In related embodiments, mouthpiece 10 can have a three oreven a four ply construction to provide additional amounts of acousticinsulation.

Microphone 40 is positioned in or on mouthpiece 10 and is configured todetect the sound 41 (herein voice sounds 41) from the diver's voice withthe mouthpiece 10 in place and generate an electrical output 42 in theform of electrical signals 42. Microphone 40 may comprise variousminiature microphones known in the art and may comprise various electricmicrophones known in the art. The microphone 40 may include or becoupled to a preamplifier 47 as well as a filter 43 for filtering outthe diver's breath sounds or other non-speech related sounds (e.g.,bubble and cavitation sounds). In various embodiments, filter 43 maycorrespond to one or more of a high pass, low pass or band pass filter.Filter 43 may also be programmable, so as to allow the user to selectvarious acoustic criteria for filtering out breathing sounds. Suchcriteria may include a particular frequency range, duration of soundand/or amplitude of sound that is filtered. Filter 43 may also beconfigured to filter out acoustic signals 52 (discussed below) generatedby acoustic transducer 50 so as to minimize feedback from transducer 50and microphone 40. In an alternative or additional embodiment, filter 43may also be configured as or include a switching device 43 s that shutsoff the generation of signals 42 by microphone 40 when the diver isreceiving acoustic signals 52 from acoustic transducer 50. In use, suchembodiments provide another approach and means for minimizing oreliminating feedback between microphone 40 and acoustic transducer 50.

Microphone 40 may be placed in any number of locations in or on themouthpiece 10, but is placed on an opposite side 22 of the mouthpiece asthat containing acoustic transducer 50 so as to minimize feedbackbetween the microphone and acoustic transducer 50 (side 22 being definedby the diver's left and right). In particular embodiments, themicrophone is placed on the opposite bite structure 30 from that ofacoustic transducer 50. In such embodiments, bite structure 30 isconfigured to dampen or attenuate any vibrations coming from acousticaltransducer 50. Also, microphone 40 may also be placed on the surface 12of mouthpiece 10, but is more preferably recessed within the mouthpieceso as to attenuate breath sounds as well as reduce the likelihood ofexposure to liquids in the diver's mouth.

In embodiments of the mouthpiece 10 having a recessed microphone 40, themouthpiece 10 can include a cavity 44 in which the microphone 40 isplaced. The cavity may include a small aperture 45 or opening to themouthpiece surface 12 to allow for acoustical conduction to themouthpiece 10. The diameter of aperture 45 can be selected to minimizethe entry of fluids into the cavity, and in various embodiments, can bein the range of 0.001 to 0.00001 inches (0.00254 to 2.54 e-005centimeter), more preferably, 0.0005 to 0.0008 inches (0.00127 to0.002032 centimeter) with a specific embodiment of 0.0007 inches(0.001778 centimeter). One or both of aperture 45 and microphone 40 mayinclude a waterproof layer 46, which may correspond to a porous materialsuch as an expanded PTFE material. Also, in embodiments of themouthpiece having a cavity 44, the microphone may also be potted incavity 44 with a sound insulating material, such as one or more curablepolymers having sound insulating properties (e.g., silicone). In use,such embodiments having a potted microphone 40 provide a means forreducing feedback between microphone 40 and acoustic transducer 50 aswell as dampening of other unwanted sounds (e.g., from the diverclenching his jaw on the mouthpiece), which may be conducted throughmouthpiece 10.

In various embodiments, an acoustic transducer 50 is positioned on theupper surface 33 of at least one of the left or right bite structures 31and 32. In specific embodiments, separate traducers 50 can be positionedon both left and right structures 31 and 32 or otherwise on oppositesides 22 (e.g., left and right sides) of mouthpiece 10. The acoustictransducer 50 is configured to transduce an electrical signal input 51(encoding or corresponding to an acoustic signal) received by thediver's communication device 100 into an acoustic output signal 52.Input signal 51 can be from one or more of another communication device100 (either another diver's or a surface ship), a dive computer, a musicplayer (e.g., an MP3 player) or other related devices. In particularembodiments, input signal 51 can be generated and/or conditioned by aprocessor 170 (described herein) or other signal conditioning device orcircuitry of communication device 100 or a processor 70 resident withinmouthpiece 10. Processor 70 or 170 may correspond to a microprocessorand can be configured to generate, and/or condition signal 51, as wellas condition signal 42 from microphone 40. Such signal conditioning ineither case can include one or more of amplification, filtering,conversion, matching and isolation.

Transducer 50 is also configured to acoustically couple to the diver'supper teeth UT to conduct the acoustic output 52 from the diver's upperteeth through the skull S to the cochlea in order to generate audiblesound in at least one of the diver's ears E when the diver is wearingmouthpiece 10. In many embodiments, the transducer 50 comprises anacoustic plate 53 (also described as a vibrating plate 53) coupled to adriver 54. The plate 53 is configured to engage and acoustically coupleto the surface of the diver's teeth and be vibrated by the driver 54responsive to electrical signal 51. Vibration of the plate 53 producesacoustical signal output 52 which is acoustically conducted to thediver's teeth and then through the bones in his or her skull to theinner ear IE including cochlea C where they are perceived as sound.Plate 53 can be fabricated from ceramic, metal, polymeric material suchas a resilient polymer, and can have a size and shape to acousticallycouple to one or more of the diver's teeth. In particular embodiments,plate 53 may have a curved horizontal shape 53 c corresponding in partto the curvature DC of the diver's dental arches DA to facilitate theplate contacting multiple teeth. Plate 53 may also have one or moreridges or other raised feature 53 r configured to enhance acousticalcoupling and conduction to the diver's teeth. In particular embodiments,ridges 53 r can be positioned to contact the center depressions in thediver's teeth.

In particular embodiments, plate 53 can be configured to have anacoustical impedance approximating or otherwise matched in some fashion(e.g., proportional, inversely proportional, etc.) to that of thediver's teeth (e.g., one or more of the upper teeth). Such embodimentscan be achieved by fabricating plate 53 from one or more dental ceramicsor other material having similar mechanical properties as the diver'steeth. Other acoustic properties can also be so matched such as theresonant frequency of the plate and the teeth. Such matching of acousticproperties can be configured to minimize acoustic losses from plate 53to the teeth or otherwise enhance conduction of acoustic signal 52through the diver's skull to the inner ear including the cochlea.

In various embodiments, driver 54 comprises an electromagnetic driver55, which can be directly or indirectly coupled to plate 53. In thelatter embodiments, driver 54 comprises electromagnetic driver 55, amovable diaphragm 56 sitting atop or otherwise coupled to theelectromagnetic driver 55, and a lever or other connecting means 57coupling diaphragm 56 to plate 53. Electromagnetic driver 55 cancomprise various electromagnetic drivers known in the speaker orearphone arts and can comprise a miniature magnet 58 which maycorrespond to a core or coil. One or more of electromagnetic driver 55,movable diaphragm 56, lever 57 and magnet 58 can be fabricated frommems-based components either separately or as a single structure. Inalternative embodiments, driver 54 (including electromagnetic drive 55)may be configured to be directly coupled to plate 53 without movablediaphragm 56 and/or lever 57.

Typically, acoustic transducer 50, including plate 53, is positioned toengage the upper (e.g., maxillary) back teeth of the diver's mouth M,but may be positioned to engage any tooth or group of teeth in thediver's mouth such as in the front either upper or lower teeth. As anaddition or alternative embodiment, transducer 50 including plate 53 mayalso be configured to engage and be acoustically coupled to the diver'supper palate (the hard palate). In such embodiments, the plate 53 canhave a curved shape matched to at least a portion of the shape of theupper palate (also known as the roof of the mouth). Such embodimentsallow for larger surface area of acoustical conduction to the diver'sskull and do not require the diver to bite down on the mouthpiece whenspeaking.

In various embodiments, mouthpiece 10 can include a sensor 60 which isconfigured to detect the diver's breath and generate an output signal 61which is used to switch off microphone 40 and/or attenuate or gate theoutput signal 42 coming from the microphone 40 to communication device100 during a time period of the diver's respiration. In the firstconfiguration (where the microphone 40 is switched off), the outputsignal 61 can be fed into microphone switching device 43 s, and in thesecond signal 61 can be sent to communication device 100 includingprocessor 170. In many embodiments, sensor 60 can correspond to aminiature flow/velocity sensor for detecting a flow rate and/or velocityof the diver's breath moving through the mouth. When the velocity orflow exceeds a threshold value, corresponding to flow or velocity of adiver's breath, the microphone 40 can be configured to shut off, and/oroutput signal 42 can be attenuated or gated by processor 170. Thethreshold value for flow and/or velocity can be selected so as to beable to distinguish between a velocity or flow rate when the diver isspeaking or breathing, the former being lower than the latter. Invarious embodiments, processor 170 and/or microphone 40 may includelogic for shutting off the microphone 40 and/or attenuating or gatingsignal 42 or 51. In specific embodiments, such logic for attenuating orgating signal 42 or 51 can be incorporated into one or more modules 190,described herein.

For embodiments where sensor 60 comprises a flow sensor, the sensor canbe positioned in a variety of locations on mouthpiece 10 for detectingthe divers' breath. In preferred embodiments, flow/velocity sensor 60 isplaced toward the front section 14 of the mouthpiece 10 (e.g., near thefront teeth), preferably in the center 15 of the front section 14, so asto be in a location in the diver's mouth having the greatestvelocity/flow rate (for example, at the peak of a velocity profile suchas a velocity profile for poiseuille flow). Such profiles can bedetermined using standard measurement methods known in the art for astandard mouth shape, size and tidal volume (or other relatedrespiratory measurement), with adjustments made for a particularindividual.

Communication device 100 can employ a variety of communicationmodalities including, without limitation, electromagnetic, such as RF,magnetic, optical, acoustic and/or combinations thereof. Referring nowto FIG. 10, in preferred embodiments, the communication device 100 cancorrespond to an ultrasonic or other acoustic transmission device 100 awhich transduces the electrical output signal 42 into an acoustic signal101, which is transmitted by the acoustical transmission device 100. Insuch embodiments, communication devices 100 a can comprise one or moreacoustic transducers 105 which transmit and/or receive acoustic energyat a selected frequency or range of frequencies. The selectedfrequencies can be in the range of 10 to 40 kHz, 30 to 40 kHz, 100 to200 kHz and 150 to 200 kHz. This frequency can be adjusted for one ormore of the depth, salinity and temperature conditions of the water.Acoustic transducers 105 may correspond to one or more ultrasonictransducers 106, which can comprise various piezo-electric materials,such as piezo-electric ceramic materials. The particular acousticaltransducer 105 and acoustical frequency can be selected based on thedesired acoustical transmission range, acoustical sensitivity,bandwidth, maximum diving depth, temperature and salinity conditions andrelated parameters.

Also, acoustic transducers 105 may be configured as both acousticaltransmitters and receivers so as to send and receive acoustical signals.In many embodiments, acoustic transducers 105 can be arranged as anarray 107 of transducers which may include a phased array formation.Array 107 can be configured to optimize one or more of the transmissionrange, sensitivity and bandwidth of communication device 100. In variousembodiments, the frequency, power settings and sensitivities ofultrasonic transducers 106 and/or array 107 can be selected to enableunderwater transmission ranges for communication device 100 up to 1500feet (457.2 meters) and more preferably, up to 2500 feet (762 meters)with even great transmission ranges contemplated. Also, communicationdevice 100 can include signal generation and selection circuitry toallow for communication over multiple selectable acoustic frequencyranges, (referred to herein after as channels). Communication device 100may also include a multiplexing device (not shown) coupled to at leastone of the transceiver or signal processing circuitry so as to allow forthe transmission of multiple signals. The multiplexing device may beconfigured for one or more of time division, frequency division or codedivision multiplexing. In alternative embodiments communication device100 can comprise an RF based device and can even include RFcommunication chip 95 described above. In these and related embodiments,RF communication chip 95 is configured to have a selected power andfrequency to enable underwater communication with other divers 210 andsurface ship 220.

Referring now to FIG. 11, in many embodiments, communication device 100can be incorporated into a portable watertight electronic (PWE) device160. PWE device 160 will typically comprise a PDA (Personal DigitalAssistant) device 160 (or other similar devices) that is worn or carriedby diver 200. PWE device 160 may also comprise or be integrated into adive watch, dive computer or other device or equipment carried by thediver, e.g., a flash light, depth gauge, regulator etc. For ease ofdiscussion, PWE device 160 will now be referred to as a dive computer160; however, other embodiments are equally applicable. Dive computer160 includes a processor 170, display 180, user input means 185 and anelectrical power source 165. Power source 165 may correspond to aportable battery such as a lithium or lithium ion battery or otherbattery chemistry known in the art. User input means 185 may correspondto a touch screen which may be separate or integral with display 180.Processor 170 includes one or more modules 190 including softwareprograms or other logic for controlling various operations of device 160including those of communication device 100. For example, in variousembodiments, module 190 can comprise a program for discriminatingbetween when the diver is speaking versus breathing using an outputsignal 61 from sensor 60 and then gate or attenuate microphone output 42and/or transducer output 51 accordingly.

In other embodiments, module 190 can comprise a program or other logicinstruction set for generating and sending various voice commands andother voice messages 102 to the diver to alert them of variousconditions, etc. and/or assist them in the performance of one or moretasks. In one embodiment, module 190 can comprise a program for thediver performing a controlled ascent whereby the program sends voiceprompts to the diver telling them how long to remain at a particulardepth before they can ascend to the next depth so as to avoid the bendsor other related conditions. The program can be configured to send theprompts in response to one or more inputs such as those from anelectronic depth gauge, electronic timer, SCUBA tank pressure or relatedgauge or sensor. Other inputs can include various messages from otherdivers 210 as well as the dive boat or other surface ships 220.

The processor 170 will typically correspond to one or moremicroprocessors known in the art and can be selected for increaseddurability, fault tolerance and pressure resistance for underwateroperation, using various MIL-SPEC criteria known in the military/navalequipment arts. Processor 170 will typically include one or more modulesor algorithms 190 for generating, conditioning and controlling signalssent to and from the mouthpiece 10, including signals corresponding tovoice messages 102 as well as controlling other operations to allow twoway voice communication by diver 200. Modules 190 may also be configuredfor computing, monitoring and communicating various physiological dataof the diver, including for example, heart rate, respiration rate, bloodpressure, blood oxygen saturation and other blood gas measurements(e.g., blood nitrogen). Processor 170 may also include other modules 190which use such data to determine if the diver is in a state ofphysiologic stress (e.g., such as stress caused by low blood oxygenlevels, “hypoxia” or out gassing of nitrogen, causing the “bends”) or aprecursor state which precedes or is otherwise predictive of a state ofphysiological stress. When such a stress state or precursor state ofstress is detected, it may be communicated by the first communicationdevice 100 to a second communicative device 110 to allow otherindividuals (such as those on the dive boat or even those onshore) tomonitor the diver(s) and alert them when it is time to ascend and/or ifdiver requires assistance.

In particular embodiments, PWE device 160 can comprise a dive computer160 or a related device that is carried or worn by the diver and isconfigured to provide the diver various voice messages 102 (alsoreferred to as spoken messages 102) including alerts, prompts andcommands using mouthpiece 10 and acoustic transducer 50. This can beachieved through the use of processor 170, audio signal generator 176,and one or more modules 190 that are configured to generate and signalvoice messages to the diver in response to one or more conditions and/oras part of a voice instruction set to the diver.

Referring to FIGS. 6 d and 10, in various embodiments, modules 190 caninclude a speech synthesis module 191 which generates audio signals 51corresponding to voices messages 102. In use, such embodiments allow thediver to perform a number of tasks and activities, including variousmission critical tasks without having the distraction of having to lookat an instrument.

Speech synthesis module 191 can comprise various speech synthesisalgorithms known in the art. Additionally in various embodiments, speechsynthesis module 191 can include the capability for generating audiosignals 52, which correspond to a selected spoken voice 103. Spokenvoice 103 can include for example, the diver's own voice, or anotherperson's voice similar to that used in aircraft navigation and controlsystems. One or both of modules 190 and 191 can include the capabilityfor the diver 200 to record specific voice messages 102 in their ownvoice or that of another individual to allow module 191 to output thosemessages to the diver 200 or another diver 210. Further, modules 190 and191 may also include the capability for the diver to record a sufficientnumber of vocalizations (in their own voice or that of anotherindividual) to allow module 191 to generate any spoken message 102 andnot just those spoken by the diver or other individual. The techniquesfor generating voices 103 from such vocalizations can include variousalgorithms known in the speech synthesis arts, for example, variousconcatenation routines 192 using stored speech units 193 derived fromthe speaker's (e.g., the divers) vocalizations. Such routines can beembedded within the programming of module 191 or they may be external.

In an additional or alternative embodiment, modules 190 and 191 can alsoinclude the ability for the diver to fine tune the voice 103 to haveselected acoustic properties (e.g., pitch, volume, etc. to theirliking). Such voice selection capability can be achieved by the use ofone or more algorithms incorporated into module 191 such as a pitchvariation algorithm 194, rate variation algorithm 195 (and otheradjustment algorithms known in the speech synthesis arts), which adjustaudio signals 51 to produce the desired voice 103. In use, suchembodiments allow the diver to select a voice that they are mostcomfortable with and can more easily hear, particularly underwater. Inthe latter case, device 160 and modules 190, and 191 can include thecapability to allow the diver to fine tune voice 103 while they areunderwater with the mouthpiece 10 in place. Accordingly, in variousembodiments device 160 can include various user input devices or otheruser input means 185 (e.g., knobs, touch screens, etc.) for making suchadjustments.

In addition to manual adjustment of voice 103, in various embodimentsdevice 160 can also include means for varying the acousticalcharacteristics of voice 103 depending upon variations in one or moreconditions experienced by the divers so as to maintain the diver'sability to hear voice messages 102 spoken by voice 103. Such conditionscan include ambient noise levels, depth, water pressure and other likeconditions. Accordingly module 191 can include one or more controlalgorithms 196 (e.g., PI, PID, etc.) which operate using an input 197which may comprise depth, pressure, ambient noise, etc. For the case ofambient noise levels, the input 197 can comprise signals 42 frommicrophone 40 or microphones coupled to device 160. In use, suchembodiments allow the diver to continue to hear commands or othermessages 102 from voice 103 during changes in their depth and in ambientnoises level (e.g., from a passing boat) which may otherwise drown outor reduce the acoustic fidelity of the voice. Module 191 can also adjustvoice 103 as well depending on the particular type of SCUBA 80, mask andmouthpiece used by the diver to account for variations in acousticalconduction and other acoustical characteristics.

Modules 191 can also be configured to modulate or otherwise adjust voice103 to account for reduced levels of conduction by bone of higheracoustic frequencies. This can be accomplished for example through theuse of pitch variation routines 195 which shifts the pitch of all or aportion of the frequency components of voice 103 to lower frequencies(e.g., make voice 103 deeper). In an additional approach for improvingconduction through the bone of the higher frequency components of voicemessage 102 or other acoustic signals 52 various embodiments of theinvention may use high pass signal routines implemented in hardware(e.g., a high pass filter coupled to an op-amp device) or in software bya module 198 running on one or both of processor 170 and 70. Such anapproach (either in hardware or software) amplifies the higher frequencycomponents of voice 103 or other acoustic signal 52 by a selected gainwhich can vary depending upon the frequency (e.g., more gain for higherfrequencies). In one approach, the amount of the gain can be determinedby doing sound conduction readings through the divers' skull and/ortaking bone density readings using one or more bone densitometerinstruments known in the art.

Device 160 can send signals 51 to mouthpiece 10 using a variety ofmodalities. For example, in various embodiments, device 160 can sendaudio signals 51 containing modulating or otherwise encoding a voicemessage 102 to mouthpiece 10 via wires 17, or alternatively may do sowirelessly using a RF chip 96 or other wireless communication device. Inanother embodiment, a second device 160′ not directly coupled tomouthpiece 10 can be used to acoustically signal voice messages 102 todevice 160 which is operatively coupled to mouthpiece 10 either viawires 17 or through use of RF communication devices 95 and 96.

As described above, various embodiments of the invention which generatevoice messages 102, for example using device 160, allow the diver toperform a number of tasks and activities, including variousmission-critical tasks without having the distraction of having to lookat gauge or other instrument. Further, voice messages 102 can includenot just data such as depth, remaining air, etc., but can includeprompts for performing one or more operations or tasks. For example, inone or more embodiments, voice messages 102 can include spokendirections for reaching a desired location, such as a dive site, or thelocation of a dive boat or that of other divers. Specific commands insuch embodiments can include without limitation, “swim up,” “swim down,”“bear to the right,” “bear to the left”. This allows the diver tonavigate to such locations while looking at their surrounding and/orwhen there is minimal lighting.

In one or more exemplary embodiments, dive computer 160 andcommunication system 5 can be configured to provide the diver with voicemessages 102 in the form of prompts for making a controlled ascent tothe surface as to avoid the bends. Specifically, the dive computer couldprovide voice prompts telling the diver one or more of how long toremain at a particular depth during the ascent, what depth he is at, howlong he has been at the depth and how soon before he can ascend to thenext depth. The computer could also provide the diver with voice updatesproviding information such as their ascent rate and whether they need tostay longer or shorter at a particular depth depending on conditions. Inaddition to prompts and updates, the dive computer may also providevoice instructions of the entire ascent plan in advance allowing thediver to get a sense of the entire plan.

While in many embodiments, mouthpiece 10 is configured for use with aSCUBA 80, in other embodiments, the mouthpiece can also be configuredfor used with a snorkel or like apparatus, allowing a snorkeler to havetwo way voice communication with another snorkeler, diver 210 or surfaceship 220. In such embodiments, the entire communication system 5,including communication device 100 can be contained in the mouthpiece10. Further, in such embodiments, the coupling element 11 can be sizedand shaped to detachably connect to a standard sized snorkel, allowingthe diver to attach the mouthpiece 10 to an off the shelf commercialsnorkel and have a skin diving version of underwater communicationsystem 5. In still other embodiments, mouthpiece 10 and communicationsystem 5 can be adapted for use with virtually any breathing apparatussuch as that used by fire and mine rescue personal, so as to allow twoway voice communications with such apparatus.

CONCLUSION

The foregoing description of various embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Manymodifications, variations and refinements will be apparent topractitioners skilled in the art. For example, various embodiments ofthe communication system 5 including the mouthpiece 10 can be adaptedfor salt and fresh water environments, as well as deep dives (e.g., 60to 200 feet (18.29 to 60.96 meters)) and cold water environments. Theymay also be adapted for use in closed circuit re-breathers in additionto standard SCUBA equipment.

Elements, characteristics, or acts from one embodiment can be readilyrecombined or substituted with one or more elements, characteristics oracts from other embodiments to form numerous additional embodimentswithin the scope of the invention. Moreover, elements that are shown ordescribed as being combined with other elements, can, in variousembodiments, exist as standalone elements. Hence, the scope of thepresent invention is not limited to the specifics of the describedembodiments, but is instead limited solely by the appended claims.

What is claimed is:
 1. A system for underwater voice communication witha diver, the system comprising: a mouthpiece configured to be worn inthe mouth of the diver, an acoustic transducer positioned on a surfaceof the mouthpiece, the transducer configured to transduce an audio inputinto an acoustic output and acoustically couple to the diver's upperteeth to conduct the acoustic output from the diver's upper teeththrough the skull to generate audible sound in at least one of thediver's ears when the diver is wearing the mouthpiece; and a portabledevice configured to send the audio input to the transducer, the audioinput corresponding to a signal received from a third party for aprerecorded spoken message identifying the third party; wherein theacoustic transducer converts the audio input into acoustic outputincluding the spoken message as substantially originally recorded, whichis conducted through the diver's skull and heard by the diver.
 2. Thesystem of claim 1, wherein the mouthpiece is adapted for connection anduse with a self-contained underwater breathing apparatus (SCUBA).
 3. Thesystem of claim 1, wherein the portable device comprises a dive computeror a dive watch.
 4. The system of claim 1, wherein the portable deviceincludes a processor configured to process the audio input to increaseconduction of the spoken message through the diver's.
 5. The system ofclaim 1, wherein the portable device includes logic resources forcontrolling the generation of the audible sound.
 6. The system of claim5, wherein the logic resources comprise a speech synthesis module forgenerating the audio input.
 7. The system of claim 6, wherein the speechsynthesis module is configured to generate the audio input, and whereinthe prerecorded message corresponds to the third party's voice.
 8. Thesystem of claim 7, wherein the speech synthesis module includes logicfor generating supplementary audio input.
 9. The system of claim 7,wherein the speech synthesis module is configured to adjust the pitch orvolume of the spoken message in response to an input.
 10. The system ofclaim 9, wherein the input is an input received by the portable device.11. The system of claim 9, wherein the input corresponds to a conditionin the diver's environment.
 12. The system of claim 9, wherein the inputincludes one of a diving depth, ambient noise level, air supply amountor rate of ascent by the diver.
 13. The system of claim 9, wherein theinput includes a stress level in the third party's voice.
 14. The systemof claim 1, wherein at least a portion of the mouthpiece comprises anelastomer, silicone or polyurethane.
 15. The system of claim 1, whereinthe acoustic transducer comprises a left and right acoustic transducerpositioned on left and right portions of the mouthpiece.
 16. The systemof claim 1, wherein the acoustic transducer comprises a piezo-electricmaterial.
 17. The system of claim 1, wherein the acoustic transducercomprises an acoustic plate coupled to a driver, the acoustic plateconfigured to be vibrated by the driver responsive to an electricalsignal input and acoustically couple to the upper teeth.
 18. The systemof claim 17, wherein the acoustic plate is configured to vibrate atabout at least one predetermined resonant frequency of the diver's upperteeth.
 19. The system of claim 17, wherein the acoustic plate has anacoustical property matched to that of the diver's upper teeth.
 20. Thesystem of claim 19, wherein the acoustical property is at least oneresonant frequency matched with the upper teeth.
 21. The system of claim19, wherein the acoustical property is an acoustical impedance.
 22. Thesystem of claim 17, wherein the driver comprises an electromagneticdriver and a movable diaphragm.
 23. The system of claim 17, wherein theacoustic plate is coupled to the driver by a lever.
 24. The system ofclaim 17, wherein the acoustic plate has a horizontal curvaturecorresponding to a horizontal curvature of a dental arch.
 25. The systemof claim 17, wherein the acoustic plate is conformable to a bite surfaceof the diver's teeth.
 26. The system of claim 17, wherein a toothengaging surface of the acoustic plate includes at least one ridge forenhancing acoustical coupling of the plate to the teeth.
 27. The systemof claim 17, wherein the acoustic plate comprises a resilient material,a polymer, a ceramic or a ceramic having mechanical properties of humanteeth.
 28. The system of claim 1, further comprising a communicationdevice coupled to the acoustic transducer.
 29. The system of claim 28,wherein the communication device comprises a receiver configured toreceive a signal used to generate the electrical signal input.
 30. Thesystem of claim 28, wherein the communication device comprises atransmitter configured to transmit an electrical signal output generatedin response to the diver's voice.
 31. The system of claim 30, whereinthe electrical signal output is from a microphone associated with themouthpiece.
 32. The system of claim 28, wherein the communication devicecomprises an RF communication device, an RF chip, or an RF transceiverchip.
 33. The system of claim 28, wherein the communication device isconfigured to send and receive signals between a second communicationdevice worn or in proximity to the diver.
 34. The system of claim 33,wherein the second communication device comprises an RF communicationdevice, a communication device incorporated into a dive computer, or acommunication device incorporated into a second mouthpiece apparatuscoupled to a SCUBA worn by the diver.
 35. The system of claim 28,wherein the communication device is embedded in the mouthpiece.
 36. Thesystem of claim 1, further comprising a portable battery coupled to theacoustic transducer.
 37. The system of claim 36, wherein the battery isembedded in the mouthpiece.
 38. The system of claim 1, wherein, themouthpiece has an exterior coupling element for coupling to an airconduit, and an interior portion coupled to the coupling element andworn in the diver's mouth, the coupling element and interior portionincluding a lumen for the passage of respired air there through, theinterior portion having a curved shape which conforms to a curvature ofthe diver's mouth; and right and left bite structures attached to theinterior portion, the left and right bite structures including upper andlower surfaces for engaging a bite surface of the user's upper and lowerteeth; and wherein the acoustic transducer is positioned on the topsurface of at least one of the left or right bite structures.
 39. Thesystem of claim 38, wherein the mouthpiece is adapted for connection anduse with a self-contained underwater breathing apparatus (SCUBA), theair conduit comprising an air hose for connection to a SCUBA tank. 40.The system of claim 38, wherein the mouthpiece is adapted for connectionand use with a snorkel, the air conduit comprising a snorkel.
 41. Thesystem of claim 38, wherein the mouthpiece is adapted to be coupled to afitting on the air conduit.
 42. The system of claim 38, wherein the leftand right bite structures are positioned on the mouthpiece to contactthe back teeth of the diver.
 43. The system of claim 38, wherein atleast one of the right or left bite structures includes a retainingflange oriented substantially perpendicular to the upper and lower bitesurfaces and which engages an inside surface of the diver's teeth. 44.The system of claim 38, wherein at least one of the left or right bitestructures is configured to be acoustically isolated from themouthpiece.
 45. The system of claim 38, wherein the mouthpiece has aunitary construction.